Proteome of hemodialysis filter membranes

Used hemodialysis filter membranes (HD filters) are discarded as waste products but represent a reservoir of valuable biological information. Numerous serum proteins are known to bind to HD filters, but whether this process selectively affects individual protein classes has not been adequately elucidated. Modern proteomics analyses offer the possibility to identify and quantify this therapy-specific subproteome and, in combination with bioinformatics methods, allow the analysis of the associated metabolic pathways. The description of the proteins at a HD filter membrane could provide insights into important modulators of the immune system or pathophysiological processes at the patient level. The aim of this project is to characterize the extracorporeal proteome of HD patients. HD filters were continuously rinsed with physiological saline immediately after the end of the HD session to remove most of the remaining blood from the capillaries. Then, a chaotropic buffer was circulated in the system for 1h by peristaltic pump to elute adsorbed proteins. Enzymatically digested proteins were desalted and purified, and separated in technical duplicate by liquid chromatography and analyzed by Orbitrap mass spectrometer, and identified bioinformatically.